We propose a comprehensive epidemiologic and laboratory investigation of an aggregate of non-Hodgkin's lymphomas related to a common source exposure to a visitor from Africa who had had an illness which was possibly infectious mononucleosis. Our preliminary investigation uncovered the occurrence of one Burkitt's lymphoma and three other non-Hodgkin's lymphomas in a group of eleven persons closely exposed to the African visitor. The visitor became ill with sore throat and malaise prior to her departure from Africa. Her illness persisted during much of her stay in the U.S. Six to eleven months after her visit, one white, adult member of each of the four households in which she had resided developed a non-Hodgkins lymphoma. One patient had extremely high titers of antibodies agains EBV with evidence of recent infection. Two of the seven non-affected but exposed individuals had elevated EBV antibody titers suggestive of recent infection. Both are spouses of the lymphoma patients. Two of the patients (and the visitor) are genetically unrelated. A close friend of one lymphoma patient also had frequent contact with the visitor. She also has high titers of EBV-antibodies with evidence of recent infection. She has an enlarged posterior cervical node. We will expand our epidemiologic investigations to identify any further contacts, to attempt to quantify the levels of exposure to the carrier and to explore potential means of EBV transmission. We propose to do further laboratory studies on the cohort of exposed individuals. We plan to obtain fresh turmor tissue during relapse for characterization as to T or B-cell origin, for study of EBV-DNA by DNA hybridization techniques and for genetic studies to detect the presence of chromosomal translocations. We will attempt to establish cell lines from the patient's peripheral blood for EBV studies an to maintain tumor cell lines in culture. We will also test for oropharyngeal EBV excretion in throat washings obtained from the patients and the carrier. We will continue to obtain serial serum samples from the cohort to observe the progression of EBV antibody titers over time. We will also obtain serum samples from the carrier and her close contacts in Africa. Thus far, our research suggests a relatively short latency period between exposure and a transmissible agent, probably the EBV, and the development of lymphomas. Additionally, this investigation suggests that a spectrum of non-Hodgkin's lymphomas may be etiologically related to the EBV. Further investigation of this exposure aggregate should provide extremely valuable new information on the causation of human lymphomas.